Chapter 5- Cladistics Flashcards Preview

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Flashcards in Chapter 5- Cladistics Deck (13)
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1
Q
How can evidence of a species which are part of a clade be obtained?
A
From the base sequences of a gene or the corresponding amino acid sequence of a protein
2
Q
Species that have recent common ancestors can be expected to have what?
A
Few differences in a base or amino acid sequence
3
Q
What does the fact that sequence difference accumulate gradually affect?
A
So there is a positive correlation between the number of differences between two species and the time since they diverged from a common ancestor
4
Q
What can be used as a molecular clock?
A
There is evidence that mutations occur at roughly constant rate so they can be used as a molecular clock
5
Q
What are two things traits can be?
A
Analogous or homologous
6
Q
What are homologous structures
A
are similar because of similar ancestry; for example chicken wing, human arm and other forelimbs
7
Q
What are analogous structures
A
Similar because of convergent evolution- the human eye and octopus eye show similarities in structure and function but they are analogous because they evolved independently
8
Q
What are cladograms
A
Tree diagrams that show the most probable sequence of divergence in clades
9
Q
Cladograms are based on what?
A
Based on base or amino acid sequences
10
Q
What are the branching points on cladograms called?
A
Nodes
11
Q
What does evidence from cladistics show
A
That classification of some groups based on structures did not correspond with the evolutionary origins of a group of species
12
Q
What were the 5 clades that had been incorrectly combined into one family in the figwort family
A
1) two small families were merged with the figwort family
2) nearly 15 genera have been moved to plantain family
3) about 12 genera of parasitic plants have been moved to the boomrape family
4) 13 genera have been transferred to a newly- created family , the lindernia family
5) two genera were moved to the newly created family, the calceolaria family
13
Q
What is a clade?
A
A group of organisms that have evolved from a common ancestor

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